Lamp.



UNITED srarps PATENT OFFICE.

EDWARD C. BROADWELL AND JOHN A. LYONS, OF CHICAGO, ILLINOIS.

LAMP.

Specification of Letters Patent.

Patented July 27, 1909.

Application filed March 18, 1905. Serial No. 250,740.

F b (11'! win/rt it m (14 "concern:

llc it known that we, lllHVARI) C. llnou w'mi. and .lonN A. Lroxs,citizens of the United r tatcs, and residents of the city of Chicago. inthe county of (look and State of lllin-ais, have invented certain newand usetul improvements in Lamps; and we do hereby declare that thefollowing is a full, clear, and exact description of the same, referencebeing had to the accompanying drawings, and to the letters of referencemarked thereon, which form a part of this specification.

This invention relates to that class of electric lamps known asincandescent and glow lamps.

l-lerctoforc in all lamps iuwhich the resistance of a filament causesthe same to bc a cheap and efi'icient metallic filament or rod j for theuse in low or incandescent lam )s in lieu of the usual filaments ofcarbon or other material. a

It is also an object of the invention to afford in connection with ametallic or partly metallic filament or rod adapted to be heated toincandescence a mantle of suitable material to enhance the lightefiiciency of the lamp.

The invention consists in the matters hereinafter described and morefully pointed out and defined in the appended claims. Y

In the drawings: Figure l is a longitudinal section of a lamp embodyingone form of our invention. Fig. 2 is an enlarged fragmentary View of theconductors, filament and a mantle therefor. Fig. 3 is a similar view ofa lamp in which the filament or rod is difierently supported. Fig. 4 isan enlarged fragmentary view of the conductors and the filament showinga mantle .in place. Fig. 5 is a similar view with the mantle omitted.

Fig. 6 is a. longitudinal section of the mantle.

Ir are conductors C and C which may be of copper of any suitableconducting material of sulliricnt size to conduct. the current withoutbecoming unduly heated. Each of said rods is provided on its outer endwith a metallic contact plate 0 and r" respectively, adapted to affordthe connection when the plugs are screwed into the sockets in circuit.

Connecting the inner ends of said rods C and C is a filament or rod/: ofany configuration contaii'iing metallic chromium. Said rod or filamentmay be supported on conductors C and G in longitudinal alinementindicated in Fig. 2 or if preferred may be supported at its ends upon apn-oximately parallel conductors C and C which extend into and through aplug i 2 as is usual with incandescant lamps, one of said condlwtorsconnecting with the outer metallic screw threaded shell (1% and theother of said conductors extending centrally through the plug andconnecting with a conducting plate 0*. In this construction, atransparent bulb or globe B surrounds the conductors and is hermeticallysealed by its connection with the plug in the usual or any desiredmanner.

The depending ends of the conductors C and C are connected by means of afilament such as before described. An incandescent mantle I) or D may besupported to inclose or partly inclose the filaments upon a rod d ofcopper, platinum or other suitable material carried on one of the screwplugs A. or may be supported on the filament.

Preferably the rod or filament is used in porous condition, there beingalloyed or chemically combined with the chromium in any quantityconsistent with maintenance of high fusion point, any chemical elementsuch as manganese which enhances the electrical resistivity as well asalso a volatile inorganic chemical element such as arsenic or a compoundthereof in proportion of say: 207.; more or less, which latter volatileelement or compound will, upon dissipation by in- Cir tense heat, leavethe chromium rod or filaembedded in such earths to pressure but sinceeflic iency of temperature rise for given heat enough by alloyingincrement varies inversely as the specific heat of the oxid, used andsince unfortunately those oxids having the lowest specific heats areeasily decomposed by glowing chromium, a loosely fitting hollowconcentric cylindric-coveringor mantle D or D preferably not touchingthe incandescent chromium rod or filament or touching it only at theends of said mantle is the best method now conceived.

In carrying out our invention, slender rods of zinc chromium, ortitanium alloy, are raised. to high incandescence in aninert gas such ashydrogen whereby the zinc is boiled away mechanical ment or rodsheretofore-in vogue. This'rod being in itself a glower ma be used bareand may be subjected to su ,ci'ent pressure to compress it into a rod ofcontinuous solidity througlfout in place of porous, provided itselectrical resistance be made high with .it a sufiicient uantity of ametal havin a tendency to orm acid oxids or metallic acids for examplemolybdenum, tungsten or manganese but as shown, we have incased the rodwith a sun yet loosely fitting mantle capable of incan escence.

Fundamentally our invention afiords an electric path of metallicchromium or its alloys vwhich may be bare, orporous and filled leaving aporous rod of much greater strength than the carbon filaing the andcovered with such oxids as by their low specific heat and high fusionpoint are able to raise the luminesence of a contiguous glowing body ythe transformation of units or quantity of heat into light. p

The bulb or transparent tube or envelop either'is vacuous or contains aninert gas under. diminished pressure.

Obviously the lamps may be of any preferred vconstruction and thefilaments may ner. v

We. claim as our invention v 1'. sThe combination with an filamentcomprising a threadof orous metallic chromium an'd'metallic' oxis-contained within the pores of said thread of a mantle of earth oxidsinclosing but out of contact with the same.

I, 2. The combination with an electric light filament comprising aporous rod of chr0- mium of suitable metallicoxids having a high beconnected in circuit in any suitable manelectric llight fusing pointcontained within the pores of the 'rod,- said metallic oxids capable ofraisluminescence of the filament and a mantle of earth oxids inclosingthe same. I

In testimony whereof we have hereunto subscribed our names in thepresence of two subscribing witnesses. I

' EDWARD c. BRoA'nWEI-Jn.

JOHN A. LYONS. I

Witnesses:

W. W. WrrHENB U RY," H ALM AR S. RUDD.

